1. Field of the Invention
The present invention relates to improvements in apparatus for transporting specimen-containers within an automated, multi-instrument clinical workcell. More particularly, this invention relates to a modular specimen-transport system that is adapted for use with each of a variety of different specimen-processing instruments of a clinical workcell, serving both to present specimen-containers to a specimen-aspiration probe of an individual instrument, and to transport specimen-containers between identical specimen-transport modules of adjacent instruments in the workcell.
2. The Prior Art
It is known in the art to perform diagnostic tests on various liquid biological specimens, e.g., whole blood, serum, urine, spinal fluids, etc., using different automated clinical instruments. In the analysis of whole blood specimens, for example, such automated instruments may include: (i) hematology instruments that operate to count and differentiate different blood cell types on the basis of their respective physical, electrical and/or light-scattering properties, and (ii) fluorescence flow cytometers that operate to differentiate different cell types by irradiating individual cells passing through an optical flow cell and detecting the fluorescence of certain fluorochromes to which the cells of interest have been conjugated or stained prior to analysis. Other automated instruments that may be used in a blood-analyzing workcell are specimen slide-makers that operate to automatically prepare optical slides of selected specimens for subsequent microscopic analysis. All of these instruments have in common a movably-mounted aspiration probe that is adapted to move vertically into a specimen-container for the purpose of aspirating a specimen for processing. While these different instruments can operate independently of each other, they are sometimes integrated or linked together to form a multi-instrument “workcell” in which a common system controller (typically microprocessor-controlled) serves to direct the operation of the individual instruments on a given specimen based on certain results to be achieved.
The biological specimens to be analyzed by clinical instruments are commonly collected in various types of sealed test tubes or containers, each usually having a puncturable cap through the above-noted aspiration probe of each instrument can enter and withdraw a desired aliquot of specimen for processing. Typically, five or six specimen tubes, each bearing encoded patient and test information in the form of a bar code, are supported for aspiration by a single rack or cassette. In a workcell environment, racks of specimen-containers are often transported between clinical instruments by a conveyor system. The latter operates to receive a rack of specimens at specimen-loading station spaced from the instruments and, as determined by the workcell's system controller, to selectively transport the rack to and from the different clinical instruments, depending on the test or processing to be conducted. Alternatively, the racks, or individual containers in a rack, may be transported to and from the different clinical instruments by a robotic arm. In either case, it will be appreciated that, if the inter-instrument conveyance fails, the workcell as a whole stops operating.
Most often, clinical instruments have their own integral specimen-transport system for receiving and advancing specimen-containers within the instrument. These sample-transport systems differ substantially in their mechanical make-up from instrument-to-instrument; as a result, they can be problematic in being integrated into a workcell architecture.
U.S. Pat. Nos. 6,444,472 and 5,720,377 disclose two different modular transport systems that are adapted for use with various clinical instruments to present racks of specimen-containers to a location at which a specimen can be aspirated or otherwise processed. Each of these rack-transport systems is a stand-alone unit comprising an input queue for receiving and aligning racks of specimen-containers to be processed; a cross-feed section to which the racks are moved in a direction perpendicular to the direction in which they are aligned in the input queue to present the containers for processing (e.g., aspiration of the contained specimens); and an output queue for receiving container racks in which the contained specimens have been processed. In the '472 patent, the rack transport module is used in combination with a robotic arm that operates to remove each individual specimen-container, one at a time, from a specimen rack located in the cross-feed section, and to transport the individual containers to one or more clinical instruments for processing. After specimen processing, the robotic arm is programmed to re-engage each specimen-container at the processing instrument, and to return it to an empty container-opening in a rack which is then advanced to the output queue. An elaborate and complex “walking beam” mechanism is used to physically lift each container rack above its supporting surface, and to advance the racks an incremental distance in the input and output queues, as well as in the cross-feed section. Thus, the specimen-container transport module of the '472 patent simply serves to advance racks of specimen-containers from an input queue to a location where the specimen-containers may be accessed by a robotic arm for processing. The module itself serves neither to present specimen-containers to an instrument for processing, nor to interface with other modules to transfer specimen-containers thereto.
In the above-noted '377 patent, the sample-transport module operates to convey racks of specimen-containers from an input queue to a location where the specimens may be aspirated from selected containers. The racks of containers are then discharged to an exit queue to await off-loading. A magnetic transport system is used to advance racks of specimen-containers along a linear path within the input queue from an input position, at which the racks are manually loaded, to a location at which each rack can be mechanically moved to a specimen aspiration station. Movement of the racks out of the input queue and into the specimen-aspiration position is effected by a conveyor belt with a series of outwardly-extending paddles. As the belt advances, the individual paddles engage the sides of the containers and thereby index the movement of the rack, one container at a time. Following specimen aspiration and testing, the specimen-container rack is mechanically urged out of the specimen-processing section by pusher mechanism that operates to engage an edge of the rack and to push the rack into the output queue. There, an indexing mechanism advances the racks to an off-loading position. While the specimen-transport module of the '377 patent may be useful in presenting specimen-containers to different clinical instruments, e.g., those used in a multi-instrument workcell, there is no discussion in this patent regarding how one might transfer specimen-container racks from one module to another, as would be necessary to link the clinical instruments of a fully automated workcell. Presumably, one would use a robotic arm or some other independent conveyor system to provide this function. Obviously, such an approach would add considerable cost and complexity to the workcell.